Quick change mounting for electric heaters



Oct. 2, 1956 R. L. PARK 2,765,392

QUICK CHANGE MOUNTING FOR ELECTRIC HEATERS Filed Nov. 16. 1953 2 Sheets-Sheet 1 Oct. 2, 1956 R. PARK 2,765,392

QUICK CHANGE MOUNTING FOR ELECTRIC HEATERS Filed Nov. 16, 1953 2 Sheets-Sheet 2 J/VVE/VTOR: P41. PH A. PARK United States Patent QUICK CHANGE MOUNTING FOR ELECTRIC HEATERS Ralph L. Park, Monterey Park, Calif., assignor to Wilbur Curtis Company, Inc., Los Angeles, Calif., a corporation of California Application November 16, 1953, Serial No. 392,324

15 Claims. (Cl. 21937) This invention relates to electric heating equipment, and is primarily directed to arrangements for quickly changing those portions of small electric heaters of the electric stove type or hot-plate type which carry the heating elements and commonly burn out or disintegrate most quickly.

An object of the invention is to provide a novel arrangement by means of which the whole heating head may be very quickly removed and very quickly replaced with a new unit.

Another object of the invention is to provide a relatively simple, and at the same time very eflicient, structure by means of which the heating unit may be quickly changed.

A'still further object of the invention is to provide a structure of the indicated nature which, while being highly efficient, is comparatively inexpensive in construction, and which also provides replacement units which also may be provided at relatively low cost and at the same time have a relatively long life.

Other objects, together with various features of construction of this improvement, will become apparent to those skilled in the art upon reference to the accompanying drawings wherein certain embodiments of the invention are illustrated In the drawings:

Fig. 1 is a small scale elevation of a single burner electric heater or hot plate;

Fig. 2 is a topplan thereof on an enlarged scale with a portion of the top housing wall broken away to disclose a mounting construction;

Fig. 3 is a horizontal sectional detail also on an enlarged scale and taken on the line 33 of Fig. 1;

Fig. 4 is a horizontal detail on a somewhat smaller scale than that of Fig. 3 and looking upward as indicated by the line 4-4 of Fig. 1;

Fig. 5 is a vertical transverse sectional detail taken on the line 55 of Fig. 2;

Fig. 6 is a bottom plan view looking upward as indicated by the line 6-6 of Fig. 5 showing the arrangement and construction of the depending socket member removed from the underlying plug member seen in Fig. 5; and

Fig.7 is an exploded view of the parts of Fig. 5, such parts being shown principally in perspective.

Having reference first to Figs. 1, 2 and 5 of the drawings, the form of the invention illustrated includes an outer square housing 10 which has an apertured top wall 12, vertical side walls 14, and, if desired, a transverse, removable bottom panel underlying the removable heating unit and associatedparts. In the top wall 12, there is provided a circular access opening 12a (Fig. 5) which is overlain by a preferably metallic annular seating cap or ring 16 having an outer, depending annular flange 18 whoselower edge rests upon the upper face of the top wall 12. Integral with the flange 18 is a sloping "ice or frusto-conical top member 20 whose inner lower edge carries an integral, downwardly directed suspension flange 21 which is in turn provided with an inwardly directed horizontal supporting rim 22 which may extend around the suspension flange 21 throughout the greater portion of the circle represented by the seating ring 16 The rim 22 thus provides a support for a heating unit or heating head 24 which includes a more or less conventional circular ceramic insulating block 25 grooved concentrically or helically to receive electric resistance wires 26 constituting heating elements. The ends of the resistance wires 26 are extended downward through small holes in the block 25, as illustrated, whereby to produce lead ends 27 which are connected with terminal bars or brackets 2% carried by a ceramic insulating socket member 31} having on opposite sides two horizontally extending integral flange portions 30a. The socket member 30 is equipped with a more or less conventional, internally disposed threaded metallic contact sleeve 31 provided for the purpose of co-operating with a plug member presently to be described. The socket member 30 is suspended from the insulating block 25 through the medium of a central suspension screw 32 which is received in a central opening 32a in the block 25. The lower end of the screw 32 is connected with the socket member 30 through the medium of an attachment plate or positioning plate 33. As best seen in Fig. 7, and also illustrated in Fig. 6, the plate 33, which is largely rectangular, overlies a correspondingly rectangular upper end of the socket member 34) and is provided at opposite sides Wlth'dC- pending integral retention flanges 33a having inturned lower portions which engage against the under sides of the ceramic flange portions 30a. The flanges 33a, thus enveloping portions of the ceramic flange portions 30a, support the ceramic socket member 30 and at the same time prevent shifting in opposite directions. In order to prevent shifting of the socket member 30 in the transverse directions, the ends of the flanges 33a are provided with integral retention fingers 3312 which are bent laterally inward as seen in Fig. 7 to engage the ends of the ceramic flanges 39a. At the center of the positioning plate 33, there is an elevation 34 (Fig. 7) which houses a nut 34a (Fig. 5) into which the lower end of the screw 32 is threaded to pull the socket member 30 up into firm position with respect to block 25. The upper face of the plate 33 also carries a plurality of upwardly directed detents 35 (Fig. 7) which enter corresponding openings 35a (Fig. 5) in the ceramic block 25, these detents thus preventing rotation of the plate 33 with respect to the block 25. Since the plate 33 cannot rotate upon the socket member 3%), these parts are thus all bound together in rigid relationship. It is also desired to prevent rotation of the assembled unit 25, 3 33 with respect to the seating ring 16. For this purpose a wide anchoring and positioning tongue 36 is fixed to the under side of a portion of the horizontal supporting rim 22, as by spot welding, and is directed inward toward a wide flat wall 37 of the socket member 30. The tongue 36 has at its inner end an integral downwardly bent Wide finger 36a, the joint between the tongue 36 and the finger 36a presenting a binding ridge 38 which bears the upper portion of the flat wall 37. By these means, when the heater head 24 is forced down within the suspension flange 21 of the seating ring 16, the spring structure provided by the tongue 36 and the finger 36a frictionally acts upon the socket member 39 to press it against the opposite side of the annular flange 21 and frictionally bind all the parts in operative, non-rotative position. This eflect is produced by reason of the fact that the suspension flange 21 provides a fairly neat fit for the insulating block 25 so that the pressure of the binding ridge 33 of the positioning tongue 36 against the flat face 37 insures firm frictional retention of the insulating block 25 in the seating ring 16.

The socket 3d, 31 is adapted to be threaded upon and receive a ceramic plug 40 by way of a threaded metallic sleeve 41 constituting in a conventional manner one of a plurality of electrical contacts which feed the electrical resistance heating elements 26 of the heater head 24. The ceramic plug 40 includes a broad base 452a which is received in a substantially rectangular opening in a horizontally positioned, transversely disposed stiff supporting web 43 mounted at its ends on slotted brackets 44 carried by the respective vertical side Walls 14 of the housing ll) and adjustably retained by small anchor bolts 45 which pass through perpendicularly disposed slots in the two parts 43 and 44 as seen especially at the left side of Fig. 2 where the slotted bracket 44 is shown as being provided with a slot 440 parallel with the side wall 14 and the supporting web 43 is shown as being provided with a slot 43a disposed in each end of the web 4-3 to extend in a longitudinal direction. By these slots 43a and 44a and the bolts 45, the web 43 is accurately adjusted, suspended and positioned on the brackets 44- through the medium of the bolts 45 whereby to center the plug 4t properly with respect to the burner head 24 and its seating ring 16. In addition to the metallic screw sleeve contact member 41 on the plug 49, this plug, in the form shown, is additionally provided with a second, disc-type contact 46 riding on a shoulder at the upper end of the ceramic plug 40. To provide a third contact, a spring-pressed pin contact 48 is mounted in an axial passage 49 (Fig. the upper end of the pin 48 bearing against co-operating spring contact 51 disposed in the inner end of the socket member 30 in a more or less conventional manner and having connection through one of the terminal bars 28 with one of the lead ends 27 leading to a respective resistance element 26. Similarly the disc-like contact 46 on the plug 44) cooperates with a third contact in the socket member 30 which is in the form of a ring contact 52 also seen in Fig. 5 and similarly connected to a terminal bar 28 leading to another of the resistance heating elements 26. By means of the three described contacts in each of the socket member 34 and the plug 42, proper connections to a corresponding number of resistance elements 26 are easily provided. The contact elements 41, 46 and 48 of the plug 40 have connection in a more or less conventional manner with terminal bars 54 on the plug 4t which in turn have connection with electric conductors 55 leading to a conventional or other switch 56 on the front of the housing 10, the switch being supplied with electric energy by way of lines 57 (Fig. 2) appropriately supplied as by means of a wall plug 58. Retention of the plug 40 in proper position in the supporting web 43, where the base 40a of the plugs is disposed in the rectangular opening 42, is effected through the medium of upper supporting flanges 6h integral with the plug 40 and its base 40a, which ceramic flanges 61) rest upon the upper face of the supporting web 43, the plug 40 being thereby supported on such web 43. To prevent withdrawal of the plug 40 and its base 40a upward through the rectangular opening 42, another pair of integral ceramic flanges 62 is employed, these flanges 62 underlying the lower face of the web 43 and opposing each other in a direction perpendicular to the direction in which the flanges 68 extend. In order to provide for easy mounting of the plug 4% with its base 40a and flanges 60, 62, the web 43 is conveniently formed of two elongated strips each of which is provided with a portion of the opening 42. These two strips and the plug memher are assembled by moving each strip laterally into position from one side of the base 49a toward the other strip so as to underlie the flanges 6t) and overlie the flanges 62, the base 40a being received in the opposing portions of the opening 42 thus provided. In this manner, as indicated in Figs. 3 and 4, the two strips overlap at 64, and

in this position they are secured together as by means of spot welding 65. For the purpose of permitting a limited amount of upward movement of the plug and its base 46a when the heater head 24 and the socket member 3d are turned down into operative position on the lug 4d, a pair of small springs '70 is provided between the corresponding under face portion of the respective strip of the web 43a and the respective underlying flange 62, the lower extremities of such springs 70 bearing in corresponding small openings in the upper sides of the flanges 62. Thus, when the heater head 24 and the socket member 343 are turned down upon the plug 4%, a little excess turning movement will be compensated for by a limited amount of upward movement of the plug 40 and its base 42a by reason of the yielding action of the springs 72. Adequate rigidity may be imparted to the transverse supporting web 43 by forming a flange 72 on the outer edge of each web strip.

As will be apparent from the foregoing description, placement of the burner head 24 upon the plug 40 and its metallic sleeve screw contact 41 is effected by lowering the head 24 into the seating ring 16, so that the ceramic block 25 is received within the depending suspension flange 21, and the flat face 37 of the socket member 30 is forced down along the binding ridge 38 of the positioning tongue 36. Thus the resilient tongue 36 and its binding ridge 38 insure a firm frictional fit of the block 25 in the flange 21, and together with the flat face 37 and straight ridge 38 provide a non-rotational relationship between the heater head 24 with its socket member 30 and the seating ring 16. In view of these conditions, rotation of the seating ring 16 causes the screw sleeve contact member 31 of the socket member 30 to rotate down upon the screw sleeve contact member 41 of the plug 40. Continuation of the rotation of the ring 16 brings the contacts and 52 of the socket member 30 into operative engagement with the contacts 46 and 48 of the plug 40. The small springs between the web 43 and the lower flanges 62 of the plug 40 yield for any extra movement required.

As a consequence of the simple installation movement as d escribed, which includes merely rotating the seating ring 16 manually until the lower edge of the flange 18 thereof rests upon the upper face of the top wall 12 of the housing, installation of the heater head 24 is readily effected. When a heater element 26 burns out, or other parts of the heater head 24 deteriorate so as to be unsatisfactory, this whole unit is readily removed merely by manually rotating the seating ring 16 in a counterclockwise direction until the screw sleeve contact member 31 of the socket 30 is unscrewd from the screw sleeve contact member 41 of the plug 40. Upon removal of this unit, the socket member 30 and the ceramic block 25 are readily disengaged from the seating ring 16 by pressing them outward through the flange 21 so as to disengage the positioning tongue 36 from the flat face 17 of the socket member 30. A new heater head 24, consisting of a new ceramic block 25 and its socket member 30, is then forced into place in the seating ring 16 and the new assembly rotated down into operative position on the plug 40.

Any type of heating head 24 other than the exposed resistance coil head illustrated may be used if desired, and obviously a series of heating units may be employed in a single housing rather than only one unit as illustrated.

Should the supporting web 43 require rigidifying, it may be stiffened by use of flanges 72 along its side edges as indicated in Fig. 4.

In addition to the specific disclosures hereof, it is intended to protect such modifications as may fall within the scope of the patent claims.

I claim as my invention:

1. In combination in an electric heater device: a hous ing having a top wall provided with an opening; a support in a lower portion of said housing; a first screw member carried by said support and having plural contact elements; a co-operating second screw member to engage said first screw member and having plural contact elements to engage the contact elements of the first screw member to complete electric circuits; a heater head mounted on said second screw member; a rotatable seating ring having an annular portion to bear on said top wall around said opening and having a depending flange rotatably and removably entering said opening and removably receiving said heater head within said flange, said ring having a central bottom opening exposing said head and passing said second screw member bodily therethrough; transverse flange means removably supporting said head in said flange; and means holding said head against rotation in said ring.

2. A combination as in claim 1 wherein said first screw member is non-rotatably received in an opening in said support.

3. A combination as in claim 1 wherein said heater head is mounted against movement on said second screw member.

4. In combination in an electric heater device: a housing having a top wall provided with an opening; a support in a lower portion of said housing; a first screw member carried by said support and having plural contact elements; a co-operating second screw member to engage said first screw member and having plural contact elements to engage the contact elements of the first screw member to complete electric circuits; a heater head mounted on said second screw member; a seating ring having an annular portion to bear on said top wall around said opening and having a depending flange rotatably and removably entering said opening and removably receiving said heater head within said flange; means removably supporting said head in said flange; and means holding said head against rotation in said ring, said second screw member having a flat vertical wall and said ring carrying a friction retention member frictionally binding against said flat wall to anchor said second screw member against rotation in said ring.

5. In combination in an electric heater device: a housing having a top wall provided with an opening; a support in a lower portion of said housing; a first screw member carried by said support and having plural contact elements; a co-operating second screw member to engage said first screw member and having plural contact elements to engage the contact elements of the first screw member to complete electric circuits; a heater head mounted on said second screw member; a seating ring having an annular portion to bear on said top wall around said opening and having a depending flange rotatably and removably entering said opening and removably receiving said heater head within said flange; means removably supporting said head in said flange; and means holding said head against rotation in said ring, said second screw member including an insulating body having flanges, and means being secured to said head and such flanges to prevent relative rotation between said body and said head.

6. A combination as in claim 5 wherein said first screw member includes an insulating body having flanges engaging said support to retain said screw member thereon.

7. In combination in an electric heater device: a housing having a top wall provided with an opening; a support in a lower portion of said housing; a first screw member carried by said support and having plural contact elements, said first screw member including an insulating body having flanges engaging said support to retain such said screw member thereon; a co-operating second screw member to engage said first screw member and having plural contact elements to engage the contact elements of the first screw member to complete 6 electric circuits; a heater head mounted on said second screw member; a seating ring having an annular portion to bear on said top wall around said opening and having a depending flange rotatably and removably entering said opening and removably receiving said heater head within said flange; means removably supporting said head in said flange; and means holding said head against rotation in said ring.

8. In combination in a quick change electric heater device: a housing having a top wall provided with an opening; a seating ring having an annular portion movably bearing upon said top wall around said opening and also having a depending member movably depending within said opening; inwardly directed supporting flange means carried by said depending member; a heater head removably retained on said flange means; first electrical attachment means carried on the under side of said heater head; means carried by said depending member of said ring and engaging and frictionally retaining said head in said depending member on said flange means against unintended axial movement; and a second electrical attachment means carried by said housing below said head for removable co-operative connection with said first electrical attachment means, said seating ring, said heater head and said first electrical attachment means being bodily removable as a unit from said opening upon disconnection of said first electrical attachment means from said second electrical attachment means.

9. A combination in an electric heater device: a housing having a top wall provided with an opening; a support in a lower portion of said housing below said opening; a first screw member carried by said support; a co-operating second screw member to engage said first screw member; a heater head mounted on said second screw member; and a seating ring having an annular portion to bear on said top wall around said opening and having a depending portion rotatably and removably entering said opening, said seating ring removably but non-rotatably receiving said heater head, said seating ring, said heater head and said second screw member being rotatably removable from said opening as a unit by unscrewing said screw members.

10. In combination in a quick change electric heater device: a first screw member having supporting base means; a co-operating second screw member to be removably mounted on said first screw member, said screw members having co-operating plural contact elements to complete electric circuits when one screw member is in cooperative position on the other screw member; a heater head mounted on said second screw member; a seating ring having an annular portion to bear upon a top wall of a housing having an opening and having a depending portion to be rotatably received in said opening, said seating ring removably receiving said heater head and providing means for supporting said head; and means holding said head in said seating ring against rotation, said seating ring, heater head and second screw member being rotatably removable as a unit from said first screw member and from said opening of a housing.

11. A combination as in claim 10 wherein said second screw member has a flat vertical wall and said ring carries a friction retention member frictionaliy binding against said flat wall to anchor said second screw mernber against rotation in said ring.

12. A combination as in claim 10 wherein said second screw member includes an insulating body having flanges, and means are secured to said head and such flanges to prevent relative rotation between said body and said head.

13. A combination as in claim 12 wherein said first screw member includes an insulating body having flanges for engaging a support to retain such screw member thereon.

14. A combination as in claim 10 wherein said first screw member includes an insulating body having flanges for engaging a support to retain such screw member thereon.

15. A combination as in claim 10 wherein each screw member is in itself an electric contact member, one screw member being receivable in the other screw member to complete an electric circuit, and an insulating member surrounding the outer screw member, the base of such insulating member providing leads to said heater head.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Italy June 6, 1933 Great Britain Nov. 19, 1935 

